A wireless charging technology is a technology of transmitting power required to wirelessly charge a battery without using a power cord or a charging connector. The related art has been used for an electric toothbrush, a home cordless phone, an electrically driven tool, and the like.
However, with a recent explosive increase in the smartphone market, use of a wireless charging technology has accelerated. The smartphone enables a user to freely enjoy abundant contents and multimedia any time, but has a short use time due to a restrictive battery capacity. The environment of the wireless charging technology in the smartphone market has greatly changed with the appearance of a wireless charging smartphone in 2010 and products with a wireless charging module for the purpose of wirelessly charging a mobile phone and a smartphone have been continuously publicized in 2011.
In 2008, the Wireless Power Consortium (WPC) was founded to establish a global standard for wirelessly charging electronic products. After the WPC published its first standard specification for devices having an output of 5 W or less in July 2010, the number of companies in a number of industries joining the WPC have continuously increased. The wireless charging technology market is expanding due to increased popularity of smartphones. The technology is expected to be used for devices having a large output such as a digital camera, a tablet PC, a monitor, a digital TV, and the like, in the future.
Further, when a plurality of wireless charging devices are present, in order to increase user convenience and the efficiency of a charging system, there is a need to determine an order of priority among the plurality of devices to be wirelessly charged, so that the objects given priority are charged first.